Is it possible to decrease the face count dramatically so I can continue working without crashing?
Another option is to set the "Display Type" to "wire" (in the "Object" tab) 

Might not be exactly what you want, especially if you're texturing, but thought it would be good to mention it here... I've realized, looking back, that my work would have often been WAY easier if I had remembered the "wire" option, or, even better, the "box" option, on some of my projects... just thought I'd mention that.